This Strategic Alliance seeks funding to develop an immunotherapeutic intervention for prescription opioid abuse that combines a lead oxycodone vaccine with immunomodulators formulated through a novel thermosensitive gelling polymer technology to enhance the post-vaccination antibody (Ab) response. Vaccines for substance use disorders (SUD) have the potential to be a long-lasting, safe, cheap, and effective intervention. Vaccines for SUD stimulate the patient's own immune system to produce anti-drug Ab that prevent drug distribution to the brain and drug-induced behavior. First-generation SUD vaccines did not meet expectations, yet demonstrated proof-of-principle in the subset of immunized subjects that achieved high levels of anti-drug serum Ab. Generation of Ab results from T cell-dependent B cell differentiation in germinal centers (GC) in secondary lymphoid organs. GC-dependent antigen-specific B and T cell differentiation is regulated by specific signaling pathways controlled by cytokines (e.g., interleukins), co- stimulatory molecules, and immune checkpoints. A wealth of pre-clinical studies have tested whether the efficacy of SUD vaccines can be improved by hapten and bioconjugation chemistry, adjuvant, peptides and protein carriers, liposome-protein nanoparticle, or polymer-based nanoparticles. In contrast, no studies have tested the broad range of available immunomodulators, which have revolutionized immunotherapy for cancer and autoimmune diseases. Using the model vaccine 6OXY-KLH, our group has identified immunological mechanisms underlying post-vaccination Ab and vaccine efficacy, and we are currently exploiting these targets for developing more effective SUD vaccines. In a screening study to identify potential lead immunomodulators, we found that co-administration of 6OXY-KLH with IL-4, or a monoclonal Ab (mAb) that blocks IL-2 signaling, increased efficacy against oxycodone. To effectively combine the 6OXY-KLH with IL-4 and/or other immunomodulators in a suitable injectable formulation, we have partnered with i-novion, a start-up company specialized in polymer technology, which has exclusive ownership of novel pentablock co-polymers (PBC). AIM1 will test whether combination of 6OXY-KLH and selected immunomodulators improves post-vaccination anti-oxycodone Ab, 6OXY-specific B cells, and vaccine efficacy in mice. AIM2 will test whether PBC-assisted delivery improves efficacy of 6OXY-KLH and leads from AIM1. AIM3 will test the efficacy of leads from AIM1 and AIM2, in blocking oxycodone-induced striatal dopamine release and conditioned place preference in mice, and oxycodone i.v. self-administration in rats. Completion of these aims will generate an immunotherapeutic intervention for prescription opioid abuse, ready for cGMP production and IND enabling studies. Completion of this project will provide data supporting a novel mechanism-based strategy for enhancing post-vaccination Ab responses, which could be applied to vaccines for other SUD or challenging diseases such as HIV, malaria, or cancer.